1. Field of Invention
This invention relates to automotive turbine engines and more particularly to a new and novel automotive step-turbine engine having in combination a primary power turbine assembly, one or more power boost turbine assemblies, and a sensor means for sequentially placing the power boost turbine assemblies in service for providing additional power to the engine over that provided by the primary power assembly as required to meet power demand as sensed by a power demand sensor means being a component part of the engine. Each of the assemblies have an air compressor coupled through an air duct to burner cans, each burner can having an electrically operated igniter means for igniting an air-fuel mixture inside the burner can and a fuel supply means for delivering fuel into the can for mixing therein with air delivered by the compressor. The fuel supply means includes a fuel pump and a fuel-regulating valve in combination for regulating the fuel flow into the burner can, said valve being controlled by the power demand said sensor means through an electrical control system actuated by the power demand said sensor means. The electrical control system thereby maintaining the rotational velocities of the rotating members within a range of velocities within which economical engine performance is achieved as power demand increases or decreases as sensed by said sensor means. The power boost turbine assemblies once placed in service are sequentially taken out of service in reverse order to that in which they were placed in service by the power demand sensor means when power output demand is reduced to the level at which the power boost turbine assemblies are no longer needed by the primary turbine assembly to maintain economical engine performance. A starter means and a pollutant reducing exhaust flow means are also included in the combination.
2. Discussion of Prior Art
In recent years turbine engines have found wide acceptance as power units for aircraft, marine and stationary application. Turbine engines have been used with some success in the automotive field, but have not received wide acceptance because of the high cost of production, high fuel consumption and emission control problems.
Turbines employed in turbine engines are reactive devices and are not positive containment or compression devices as is the case with most internal combustion engines currently employed in automotive engines. Turbine blade speed or rotational velocity of the turbine wheel is very critical in turbine powered engines presently in use. Generally this velocity must be kept within plus or minus ten percent of the optimized rating of the turbine blade speed and in general this is not possible in engines currently being investigated for automotive applications. Presently used engines are not economical to operate because of blade speed of the turbine is not held within the critical tolerances when engine power change requirements occur. Prior art turbine engines generally must be designed for specific load requirements commensurate with the economical turbine blade speed range. These turbines are not operated economically at power requirements which cause the turbine blade speed to vary outside the designed limits and are generally not economically adapted to varying load condition requirements of automotive uses. Turbine engines currently available for automotive use generally rely upon continuous running compressors for providing and controlling the air intake into a combustion chamber and a fuel intake control system for controlling the fuel intake to the combustion chamber. These engines generally suffer from severe time lag in providing increased power output on demand and conversely, an excessive time lag is experienced when power demand is reduced. These requirements extrapolate into relatively expensive manufacturing costs for automotive turbine engines described in prior art. The present invention overcomes the disadvantages of the prior art automotive turbine engines in that the optimum turbine rotational velocity is maintained by selectively activating the deactivating successively power boost turbine assemblies to provide additional power in combination with a continuously operating primary power turbine assembly. The additional power boost turbine assemblies are activated or de-activated automatically by an electrical control system actuated by a power demand sensor means successively as the drive shaft load increases or decreases respectively and the minimum power requirements are provided by the primary power turbine assembly.
The rotating parts in each of the power assemblies performing similar functions rotate in synchronism at the same rotational velocity and the power boost turbine rotating parts rotate in a near vacuum when the power boost turbine is not in service thus reducing the frictional drag of these rotating parts to a very low value. This feature also substantially eliminating power surges when the power boost turbine assemblies are placed in or taken out of service as determined by the power demand sensor.
Furthermore, the engine of the present invention provides greater economy than is available in prior art engines because the turbine blade speed is maintained within the range of greatest economy of opeation at all power demands for which the engine is designed to operate as an automotive engine and the maximum power demand operating range is determined by the number of power boost turbine assemblies employed to provide increased power over that provided by the primary power turbine assembly.